Giant prehistoric snake snacked on baby dinosaurs

By John Pickrell and Melissa Leong 5 March 2010
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Dino-era relative of Aussie snakes enjoyed hatchlings, over easy.

THE DISCOVERY OF A 67-million-year-old fossil snake coiled around the remains of a newly-hatched dinosaur egg indicates that this large serpent, Sanajeh indicus, was a predator of baby sauropod dinosaurs.

According to researchers at the University of Michigan, as relatives of this species are found in Australia today, the discovery suggests that India remained attached to Australia and other parts of the southern landmass of Gondwana for far longer than experts had previously supposed.

The research is detailed this week in the journal PLoS Biology.

Big snack

The fossil, found in the nest of a herbivorous titanosaur in Gujarat, India, consists of an almost complete skull with lower jaws, vertebrae and ribs. Titanosaurs were some of the largest of the sauropods, which were enormous, four-legged herbivores with long necks.

Burial was rapid and deep said experts who examined the paleoenvironment of the site, which is the reason this snapshot in time has been so well preserved. They think that a pulse of slushy sand and mud released during a storm caught the sauropods in the act of hatching and the snake in the act of feasting upon them.

“This is the first direct evidence of feeding behaviour in a fossil primitive snake, and shows us that the ecology and early evolutionary history of snakes were much more complex than we would think just by looking at modern snakes today,” said study co-author Jason Head, a snake palaeontologist at the University of Toronto-Mississaugua, Canada.

The fragile fossil was first discovered in India in the late 1980s by Dhananjay Mohabey at the Geological Survey of India. But its true importance was not realised until much more recently when it was examined by experts including Jason and dinosaur palaeontologist Jeff Wilson from the University of Michigan in the US.

A mystery unravelled

“I saw the characteristic vertebrae of a snake beside the dinosaur eggshell and larger bones, and I knew it was an extraordinary specimen, even if I couldn’t put the whole story together at that point,” Wilson said. “I just knew we needed to examine it further.” Jason was called in to help them fill in the gaps in their knowledge.

The 3.5 m giant snake is an ancient ancestor of the ‘macrostomatan’ group of snakes that have mobile skulls and wide gapes today, he said. Most primitive snakes lacked the jaw apparatus to swallow large prey. “[But] the evolution of a large body size in Sanajeh would have allowed it to eat a wide range of prey, including dinosaur hatchlings.”  

John Scanlon, at the Riversleigh Fossil Centre in Queensland, told Australian Geographic: “There has long been a view that the adaptive radiation of snakes was associated with diets based on small mammals, with other important prey being things like lizards and salamanders… including small dinosaurs as well greatly expands our concept of the ecological niche of early snakes.”

“Hundreds or thousands of defenceless baby sauropods could have supported an ecosystem of predators during the hatching season,” added Jason. Those dinosaurs lucky enough to survive the first few moths would have undergone an immense growth spurt which made them big enough to safeguard against predation from Sanajeh-sized predators by the time they were one year old, he added.

Sanajeh indicus roughly translates as “ancient gaped one from the Indian subcontinent”.